In my previous blog post, I reported on a new Web tool called CrystalNets, a tool for topology identification of crystalline materials, developed by Lionel Zoubritzky and François-Xavier Coudert. A gathered a test set composed of 100 different MOFs and compared CrystaNets with TopCryst. The topology of the underlying net of these MOFs were correctly ..read more

Determining the topology of the underlying net of a MOF can be a difficult and tedious task, especially if you are a beginner in the field. In order to be able to operate ToposPro on a profound level and to roughly understand how it works, it will ususally take you at least a 5-day workshop ..read more

Picture: Christian Rewitzer – CC BY-SA 3.0 Crystal structure (click on the pictures to download the VESTA file): (K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).) For a 3D interactive version, see here: https://skfb.ly/ozQXK Refs.: [1] J.A. Mandarino, E. Matzat, S. J. Wiliams, Zemannite, a ..read more

Recently, I have been immersed in the vast world of intermetallic phases, in particular those with an ordered superstructure of either cubic-closest packed (ccp) or body-centred cubic (bcc) parent structure. They caught my interest, because some of the researchers in that field are paying particular attention to how the densest-packed layers/planes look like and how ..read more

Michael Fischer, known as @ZeoliteMiFi on twitter, created a mock .cif file that allows visualisation of the periodic table in a structure visualisation software like VESTA. With that, one can see at one glance how different elements are shown. He kindly provided the CIF and you can download it here. May be reused for all ..read more

In a very interesting article by Giese and Seppelt from 1994 [1] the question of the preferred coordination geometry for the coordination number 7 is explored. Until then, it has been shown that the pentagonal bipyramid is preferred for main group elements (for instance in the compound IF7), although this geometry results in an overall ..read more

Despujolsite Named in honor of Pierre Despujols (1888–1981), the founder of the Moroccan Geologic Survey (“Service de la carte géologique du Maroc”) The mineral was first observed in 1962 in manganese ore samples from Tachgagalt (Anti-Atlas, Morocco). Formula: Ca3Mn(SO4)2(OH)6  · 3 H2O Space group: P-62c Crystal system: trigonal Crystal class: -6m2 Lattice parameters: a = b ..read more

I’ve started another ‘230 project’. This time it is concerned with space group diagrams. Of course, the No. 1 source for such diagrams, i.e. symmetry element and general position diagrams, is Volume A of the International Tables for Crystallography (ITA). As valuable as they are for the daily life of a crystallographer, they are unsuitable ..read more

Kapellasite Named after Christo Kapellas (1938-2004), collector and mineral dealer of Kamariza, Lavrion, Greece Kapellasite is isostructural with Haydeeite [Cu3Mg(OH)6Cl2] Kapellasite is a metastable polymorph of Herbertsmithite Formula: Cu3Zn(OH)6Cl2 Space group: P-3m1 (No. 164) Crystal system: trigonal Crystal class: -3m Lattice parameters: a = b = 6.300(1) Å, c =  5.733(1 ..read more

Blödite (also Bloedite) named after the German mineralogist and chemist Karl August Blöde (1773 – 1820) fun fact: the German adjective “blöd(e)” means “stupid” Formula: Na2Mg(SO4)2  · 4 H2O Space group: P21/a Crystal system: monoclinic Crystal class: 2/m Lattice parameters: a = 11.126(2), b =  8.242(1) Å, c = 5.539(1) Å, α = 90 ..read more